SrTiO\(_3\)  can be described as a semiconducting superconductor: as a function of carrier density, its ground state evolves from an insulator to a normal metal to a superconductor. A schematic phase diagram is shown in Fig. REF a, roughly summarizing a very large body of work on substitutionally-doped SrTiO\(_3\) , LaAlO\(_3\) /SrTiO\(_3\) , LaTiO\(_3\) /SrTiO\(_3\)  and ionic liquid-gated SrTiO\(_3\) , see e.g. [1]}, [2]}, [3]}, [4]}, [5]}.
